From steel beams to American icon: Golden Gate Bridge celebrates 75 years as an engineering masterpiece

The orange hue of the Golden Gate Bridge was an accident of history.

San Francisco owes the iconic color of its bridge to Irving Morrow, the consulting architect, who noticed the striking reddish-orange hue of the primer coat, and lobbied to have it made permanent.

From DailyMail

It was built as the country was emerging from the Great Depression, and grew into an icon of America.

It was also heralded as an engineering marvel when it opened in 1937.

It was the world's longest suspension span and had been built across a strait that critics said was too treacherous to be bridged.

But as the iconic Golden Gate Bridge approaches its 75th anniversary over Memorial Day weekend, the generations of engineers who have overseen it all these years say keeping it up and open has been something of a marvel unto itself.

Dream becomes reality: The idea for a bridge across the Golden Gate strait, where San Francisco Bay meets the Pacific Ocean, was championed by the engineer Joseph Strauss in the 1920s

Under construction: The bridge was completed in 1937 and became the largest suspension bridge ever built; workers, right, carried heavy iron beams in 1936

Such great heights: Painter Don Dulac, the oldest on the painting crew, scales dizzying heights top of the North Tower, paint brush in hand

Crews had to install a bracing system after high winds lashed and twisted the span in the 1950s, raising fears it would collapse.

Years later, they had to replace vertical cables when they were found to have corroded in the bridge's damp, foggy climate, potentially destabilizing the span.

The bridge, which rises majestically above a Civil War-era fort on the San Francisco side and arches across to the Marin County headlands on the north side, is currently in the midst of a seismic upgrade that has seen many of its key structures replaced or modified. 

Plans for a moveable barrier to separate north and southbound traffic and a net system to prevent suicides are also moving forward.

'When (one of the bridge's designers) made his final speech during opening day ceremonies in 1937, he said, `I present to you a bridge that will last forever,'' said Daniel Mohn, the bridge's former chief engineer, who co-authored a book about the span.

'What he should have said is, `I present to you a bridge that will last forever if properly maintained.'

The idea for a bridge across the Golden Gate strait, where San Francisco Bay meets the Pacific Ocean, was championed by the engineer Joseph Strauss in the 1920s.

Engineering marvel: On completion, the steel bridge was the longest suspension bridge main span in the world and cost approximately $35 million

Darker side: With a drop of 245 feet to the water below, the bridge has become the biggest suicide site in the world

Slowly but surely: By 1935, construction was well underway and workers began to lay further foundation to the bridge's towers

Impossible dream: The bridge had to be light enough to hang from its own cables, but still strong enough to withstand the strait's fierce winds and the possibility of earthquakes - some said it was impossible

Incredible feat: The tourist attraction was the world's longest suspension span at the time, built across a strait that critics said was too treacherous to be bridged

Strauss's original design, submitted to San Francisco city officials in 1921, called for a hybrid cantilever-suspension bridge.
The idea for a full-suspension span - the design that was ultimately built - came later.

At a little more than three-fourths of a mile in length, the Golden Gate Bridge would become the world's longest suspension span.

It had to be light enough to hang from its own cables, but still strong enough to withstand the strait's fierce winds and the possibility of earthquakes. Some said it was impossible.

Engineers also had to calculate all the potential forces on the bridge without the help of computers.

'In those days, you had (notebooks) and a number two pencil and you wrote it out, did all the math at your desk,' said Kevin Starr, a history professor at the University of Southern California, who has also written about the bridge.

Eleven men died during construction from 1933 to 1937 - ten of them when scaffolding fell through a safety net that had been set up to protect workers.

The conditions were difficult, cold, foggy and windy, and workers who helped construct supports for the south tower had to contend with dangerous tides.

Looking on: A young family gazed out into the bay looking at the nearly-completed bridge; it opened to the public on May 27, 1937

But it was the wind that would continue to vex engineers years after the bridge's completion.

In 1951, it was closed for several hours when wind gusts approached 70 mph and caused the bridge to flutter.

It was twisting so badly, Mr Mohn recalled during a recent phone interview, that the light standards at the centre of the span were striking the main cables.

'It sure almost destroyed the Golden Gate Bridge,' he said.

The Tacoma Narrows Bridge in Washington - a suspension bridge whose designer also worked on the Golden Gate - had twisted and snapped in about 40 mph winds a little more than a decade earlier. That 1940 collapse was captured on film.

Although the Golden Gate Bridge had stiffening trusses that made it less susceptible to wind, it did sustain damage, Mr Mohn said.

Officials decided to add lateral bracing that made the trusses more stable and reduced the chances of the bridge going into a potentially catastrophic twisting motion.

In the mists: The top towers of the bridge peek out from clouds and mist, with the signature red paint offering a stark contrast to the white fog

Nestled in: An August moon appears to rest on the top of the south tower of the Golden Gate Bridge, with the city's iconic skyline as background

Anticipation: On Sunday, May 27, 2012 it will be 75 years since the famous red bridge was opened, linking the northern point of the San Francisco peninsula to Marin County across the opening of the San Francisco bay

The bridge would be able to withstand winds of 70 mph today although the goal is to eventually increase its tolerance to 100 mph, according to Ewa Bauer, the bridge's current chief engineer.

The wind is not the only element to take its toll on the span. The damp, foggy air has also kept its painters and engineers busy.

'You couldn't have put the bridge in a more corrosive atmosphere than in the middle of the Golden Gate with that salt fog coming in,' Mr Mohn said.

Engineers discovered in the 1970s that the bridge's suspender ropes - the vertical cables that connect the deck to the main cables - had corroded, some so badly that they could be picked apart with a pocket knife.

The problem in part, Mr Mohn said, was that bridge maintenance had been neglected for many years, particularly during World War II. A design flaw also hastened corrosion.

All of the cables were replaced in the mid-1970s.

There was another scare on the bridge during its 50th anniversary in 1987 when an estimated 300,000 pedestrians gathered on the span, which was closed to vehicle traffic.

The weight of the crowd flattened out the arch of the bridge deck and caused some revelers to suffer motion sickness as the bridge swayed.

Although the bridge supported its heaviest load in 50 years that day, Mohn would later conclude the weight and movement had not exceeded its design capacity.

Today, among the engineers' most pressing concerns is the potential effect of a major earthquake.

Expansive: A seagull flies near past the 1.7-mile bridge on May 24

The 1989 Loma Prieta earthquake, which occurred during a live broadcast of the World Series, caused two 50-foot sections of the San Francisco-Oakland Bay Bridge to collapse.

The Golden Gate Bridge was not damaged.

But the quake still spurred bridge officials to undertake a massive retrofit of the span - a $660 million project that began in 1997 and is still underway.

Bridge pylons have been reinforced with steel and towers under the bridge's two approaches were replaced, all while keeping the bridge open and its appearance unchanged.

Retrofitting the suspension span is the project's final phase although experts say its flexibility makes it less vulnerable in an earthquake.

'If I knew when an earthquake was coming, I'd get to the suspension span of the Bay Bridge or the Golden Gate Bridge,' said Abolhassan Astaneh-Asl, an engineering professor at the University of California, Berkeley who studied the Golden Gate Bridge after Loma Prieta.

'They are safest places to be.'

The goal is to withstand an 8.1-magnitude earthquake when the retrofit is completed years from now.

The bridge, like other infrastructure, has a lifespan.

But Bauer and Mohn say with proper maintenance, the Golden Gate Bridge will endure.

The retrofit project alone will buy the span another 150 years, Bauer estimated.

'I believe the bridge was built to absolute great standards of workmanship,' she said on a recent morning at a vista point overlooking the span.

'What we are doing right now is repairing...and you can truly do it indefinitely.'

Funny polar bears

Laziest polar bear ever!

Straight from the Arctic to your screen, here's the laziest polar bear ever recorded.

Cute and funny polar bear handstand

Check out this funny polar bear doing a handstand and his hind paw sticking out of the water.

Visit oneworldoneocean.org for more Arctic videos and learn why we should protect this pristine environment and its inhabitants.

NOAA, National Safe Boating Council promote National Safe Boating Week

Boat flips at New Brighton Beach : let Darwin's theory continue

From NOAA

NOAA’s National Weather Service and the National Safe Boating Council (NSBC) have partnered again to encourage recreational boaters to know their risks, learn the rules, and be prepared before taking the helm this summer during National Safe Boating Week: (May 19 to 25).

According to the U.S. Coast Guard, there were more than 4,000 boating accidents, including 758 deaths, in 2011. Seventy percent of all fatal boating accident victims drowned, and of those, 84 percent were reported as not wearing a life jacket.
Once in the water hypothermia can become a significant threat to survival even if wearing a life jacket.
To increase awareness about the dangers of hypothermia, the NSBC and NOAA have enlisted assistance from former college football player and boating tragedy survivor Nick Schuyler. Schuyler was the lone survivor of a boating accident while fishing off the Florida Gulf coast in February 2009. Interviews with Schuyler are available online and provide lifesaving information about hypothermia as well as the importance of being prepared.

 “Before going out on the water, check the marine weather forecast and then stay informed with a NOAA Weather Radio,” said Jack Hayes Ph.D., director, National Weather Service.
“We want boaters to be part of our Weather-Ready Nation. Weather can change very quickly on the water. The sudden emergence of dark clouds, increasing winds, torrential downpours and lightning can turn a relaxing time on the water into a dangerous situation.”

NOAA and the NSBC have launched a series of boating safety public service announcements to highlight important boating safety topics, including hypothermia; the importance of always wearing a life jacket; distress radio beacons; winds and waves, thunderstorm safety; understanding your marine forecast; and boating under the influence.

This Inflatable Life Jacket Educational vieo is an educational approach to educating boaters about inflatable life jackets.

The NSBC administers the North American Safe Boating Campaign “Wear It!” designed to educate boaters about the importance of life jacket wear while introducing them to the different styles that are available, including inflatable life jackets.
“Wear It!” is produced under a grant from the Sports Fish Restoration and Boating Trust Fund, administered by the U.S. Coast Guard.
“Lives can be saved by improving the knowledge and skills of recreational boaters,” said Virgil Chambers, executive director, NSBC.
“Boaters can have fun and stay safe by wearing a life jacket, having the proper equipment onboard, knowing what the weather conditions will be, and abstaining from alcohol while boating.”
NOAA and the NSBC encourage recreational boaters to prepare before they go out on the water by following these guidelines:

• Know your risk: Have an understanding of the body of water you want to boat in. Learn the rules of boating before taking the helm by taking a safe boating course. Check the marine weather forecast before going out on the water. The weather can change quickly, so plan for all types of weather hazards.

• Be prepared: Make sure your vessel has the required equipment such as life jackets, a first aid kit, and distress signals. Develop an emergency plan with more than one way to get your boat out of trouble. Create a float plan and tell a friend of your whereabouts and when you plan to return. Obtain and pay attention to NOAA Weather Radio and understand marine watches, warnings and advisories.

• Be an example: Share with your friends, family, co-workers, and your social media network safe boating tips, such as the importance of wearing a life jacket and taking a safe boating course. The information you share might just save their lives, too.

NOAA, through its National Weather Service, is dedicated to supplying the most up-to-date and accurate weather information throughout the U.S. coast, coastal and offshore waters, the Great Lakes, and the open oceans.
NOAA’s National Ocean Service provides the navigation services that protect lives, strengthen the maritime economy, and position America for the future.
Download NOAA’s free nautical charts BookletCharts today.
The National Safe Boating Council (NSBC) is the foremost coalition for the advancement and promotion of safer boating through education, outreach, and training.
The NSBC accomplishes this mission by promoting outreach and research initiatives that support boating education and safety awareness; improving the professional development of boating safety educators through training; and developing and recognizing outstanding boating safety programs. More information about the NSBC and its programs, is available online.
NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.
Join NOAA on Facebook , Twitter and our other social media channels.

CryoSat goes to sea

Gravity field over the Pacific Ocean’s Emperor Seamounts based on CryoSat, ERS and Geosat satellite altimeter measurements of ocean-surface height.

At this scale, the gravity field of the ocean reflects seafloor topography, called bathymetry.

The improved radar measurements from CryoSat will be used to improve bathymetry. The measurements will be used in the next generation of the seafloor maps in Google Earth.
Credits: Scripps Institution of Oceanography/NOAA

From ESA

CryoSat was launched in 2010 to measure sea-ice thickness in the Arctic, but data from the Earth-observing satellite have also been exploited for other studies.
High-resolution mapping of the topography of the ocean floor is now being added to the ice mission’s repertoire.

The main objective of the polar-orbiting CryoSat is to measure the thickness of polar sea ice and monitor changes in the ice sheets that blanket Greenland and Antarctica.
But the satellite’s radar altimeter is not only able to detect tiny variations in the height of the ice but it can also measure sea level.

The topography of the ocean surface mimics the rises and dips of the ocean floor due to the gravitational pull.

An Earth-orbiting radar cannot see the ocean floor, but it can measure ocean-surface height variations induced by the topography of the ocean floor.

The gravitational pull of the seafloor produces minor variations in ocean surface height.

Seafloor mapping by ships is much more accurate than radar altimeter mapping, but to date only 10% of the seafloor has been charted this way.

A complete mapping of the deep oceans using ships would take 200 ships navigating Earth, 24 hours a day, for an entire year at a cost of billions of dollars.

Mapping using satellite radars can cover a larger area in a shorter amount of time.

When interesting features are discovered in satellite measurements, they can later be surveyed in fine detail by ships.

Credits: Scripps Institution of Oceanography

Areas of greater mass, such as underwater mountains, have a stronger pull, attracting more water and producing a minor increase in ocean-surface height.

Therefore, instruments that measure sea-surface height incidentally map the ocean floor in previously uncharted areas.

There have been several recent global gravity missions, such as ESA’s GOCE satellite, that provide extraordinarily accurate measurements of gravity at the spatial resolution of hundreds of kilometres.

CryoSat determines variations in the thickness of floating sea-ice so that seasonal and interannual variations can be detected.

The satellite also surveys the surface of continental ice sheets to detect small elevation changes.

Information on precise variations in ice thickness will further our understanding of the relationship between ice and climate change.
Credits: ESA /AOES Medialab

But CryoSat’s radar altimeter can sense the gravity field at the ocean surface, so that seafloor characteristics at scales of 5–10 km are revealed.
This is the first altimeter in 15 years to map the global marine gravity field at such a high spatial resolution.

Recent studies at the Scripps Institution of Oceanography in San Diego, USA, found that the range precision of CryoSat is at least 1.4 times better than the US's Geosat or ESA's ERS-1.

They estimate that this improved range precision combined with three or more years of ocean mapping will result in global seafloor topography – bathymetry – that is 2–4 times more accurate than measurements currently available.

“We know more about the surfaces of Venus and Mars than we do about the bathymetry of deep oceans,” said David Sandwell from the Scripps Institution of Oceanography in the US.
“This new mapping from CryoSat will revolutionise our understanding of ocean floor tectonics and reveal, perhaps, 10 000 previously uncharted undersea volcanoes.”

Most satellite radar altimeters such as the one on the joint CNES/NASA/Eumetsat/NOAA Jason-2 follow repeated ground-tracks every 10 days to monitor the changes in ocean topography associated with ocean currents and tides.

CryoSat’s 369-day repeat cycle provides a dense mapping of the global ocean surface at a track spacing of over 4 km.
Three to four years of data from CryoSat can be averaged to reduce the ‘noise’ due to currents and tides and better chart the permanent topography related to marine gravity.

US and Canada charts layers display problem

This morning some electrical incident occurred on our servers : one of our main servers crash in our datacentre.

This outage only affects the display of the US NOAA and Canada CHS layers on our website and on the 'Marine US' iPhone/iPad app.

We're very sorry for any inconvenience caused.

It will take about one week to fully restore the service for displaying these two North American layers again.

The last fisherman : who's got their hands on all our fish?

An overhaul of the law that governs fishing in Europe only happens every 10 years, so we need to make sure that this time, it works.

We want a Common Fisheries Policy (CFP) that supports sustainable fishing, ends discards and puts the health of our seas first.

Be a fisherman's friend.

From TheGuardian

Greenpeace has spent a lot of time lately on wharves, docks, piers and beaches.
The story we're hearing is the same the coast long; the UK's low-impact, small-scale fishing industry is on its last legs.

These fishermen, most of whom are part of the inshore under-10-metre fleet, tend to land high quality fish, using methods that do little or no damage to the local environment.
But they aren't rewarded.
Quite the contrary: despite comprising 77% of the active UK fleet, they have access to only 4% of the country's quota.

So who's got their hands on all our fish? (It's worth remembering they are our indeed our fish; they're a public asset, a common resource).
No one really knows who holds UK quota, but what we do know is that the answer mostly involves those with the most economic clout and ability to throw their weight around.
In a gradual process bordering on privatisation by stealth, the resource of the many has fallen into the hands of a few.

As the long-time Hastings fisherman John Griffin puts it: "It's definitely the 'greener' side of the industry that's suffering.
We're as morally correct as we can be, we don't hide anything and we try to be as green as possible; we're doing our best but we're the ones being pushed out."

Which brings us to an unprecedented alliance between UK fishermen and Greenpeace.
Today we're launching a campaign called Be a Fisherman's Friend, to save the UK's struggling inshore fleet, and thereby protect our fish.
It's a common myth that Greenpeace is anti- fishing; we just want fishing rights to be given to those who fish in the right way.

Most people are aware the system's broken.
In fact railing against the EU's Common Fisheries Policy (CFP) is a British political ritual, conducted in language as familiar as the Lord's Prayer or the football results.

So well-worn is this tale that it's rare for anyone to even question its basic veracity, or to ask why, if it's so broken, successive fishing ministers have done so little to fix it? Yet if we cannot find an answer to this question, we will continue to be hamstrung by a policy that's trashing our oceans and failing our fishermen.

A reform of the CFP, currently underway in Brussels, provides a once-in-a decade opportunity to alter things so that the system rewards those fishing sustainably.

But let's go back. How did we get to the point where EU fisheries policy allows a tiny number of high-impact operators to dominate how we manage our oceans and fish stocks, despite their fishing methods being so destructive?

"Efficiencies" in fishing have been progressing at the rate of around 3% a year for decades. Ever-more powerful boats go further and faster, with ruthless and indiscriminate fishing methods, hunting down fish in hundreds of miles of ocean using sophisticated sonar systems.

The inevitable result is that fish stocks decline: 72 % of European fish stocks are now depleted.
If we continue to fish as we are, 91% of European fish stocks will be at unsustainable levels within the next decade.

In response to the problem of "over-capacity" [read: too many factory-style boats catching too many fish], boats have had to be forcibly removed from the industry.
And because the more "efficient" boats and skippers make the most money, they're often the ones who remain in the game while others are forced to leave.
Fishing rights, money and influence have become increasingly concentrated in the hands of a relatively few individuals and businesses, who in turn act as a powerful and entrenched lobby for the kind of industrial scale fishing practices that maximise profit at the expense of local employment and the local environment.

In the UK, this process has been exacerbated by successive governments' chronic mismanagement of the national quota allocation, which is what's left the inshore fleet with access to only 4% of quota.

The UK government has also allowed those who control the lion's share of the quota to treat it as a tradable commodity.
Unused quota is leased out at exorbitant prices, maximising profits for the quota "owner" at the expense of ordinary fishermen in coastal towns up and down the country.
We're on our way to fishing rights being traded like subprime mortgages.

Evidence shows that those who fish selectively and with least environmental impact offer the greatest benefits to the economy.
One recent analysis estimated that for every tonne of cod landed, trawlers delivered negative economic value ranging from -£116 for the smallest trawlers to almost -£2,000 for the largest. Gillnets (a lower impact fishing method) in contrast generated a net +£865 of value.
Yet between 2006 – 2008, trawlers landed almost 6,000 tonnes of cod, while gillnets landed less than 3% of this – just 163 tonnes.

The CFP reform is an opportunity to sort out the mess.
It is now up to the government to pursue reforms at home and in Brussels, which will capture the economic benefits of sustainable fishing. Giving priority access to those who use selective, low-impact methods and provide the highest levels of local employment should become the guiding principle of fisheries management.

This won't be easy. Vested interests will continue to claim that "batting for Britain" is simply about grabbing a greater share of the EU pie, rather than securing a truly radical reform of EU and UK fisheries management.
For the sake of our fishermen, our fish stocks and the health of our coasts and seas, this government and the fisheries minister, Richard Benyon, must take a different view.

From WP : the end of fish, in one chart

Links :

• TheEconomist :  Plenty more fish in the sea
  

The most beautiful boat race in the world ?

 Billowing sails: Some of the 99 boats taking part in the Al Gaddal dhow race from the island of Sir Bu Nair, near the Iranian coast to Dubai

From DailyMail

Skimming the surface of the sea, brilliant white sails billowing in the wind, they are a timeless image of elegance.
But the 99 dhows taking part in this year’s Al Gaffal race are not simply a stunning site on a beautiful day.

 Mission: The race was begun to encourage the long tradition of dhow building, which had slowly been dying out

They are also keeping alive an ancient tradition of shipbuilding which stretches back to Greek and Roman times.

Elegant: The dhows are some of the most easily recognisable boats operating in the Emirates - or anywhere else in the world

The ships – recognisable by their triangular lateen sails – were once used on the trade routes across the Indian Ocean.

Finish line: The race ended off the coast of Dubai. The distinctive Burj hotel - can be seen in the background of this picture

They are now a less common site.
But the Al Gaffal allows thousands of spectators, positioned on the Dubai shore, to see them in all their glory.
In its 22nd year, the race at Sir Bu Nair Island, near the coast of Iran, and finishes just off the emirate state’s International Marine Club.

 Mists of time: There are records of this boat type being made in Greek and Roman times but it is unclear when the first dhow was built

It began at 6.30am and by midday, many of the 60ft boats were crossing the finishing line.
Organisers chose Sir Bu Nair as the starting point as it is where pearl divers – who were the early staple of the Dubai economy – stopped to rest on their way home from months at sea.